PM5 or PM9 Help please.

SweetOh

Well im sorry to say my blue wagon was jerry rigged when i bought it. It came with a PM9 ecu that was recently put in, cause the face plate foot guard thing was sitting on top of the spar tire.
Before i fixed the timing belt i though to switch the ecus. The PM5 from the brown wagon. And i been running with that ever since. But now I’m curious will the PM9 make any improvement, or not?

what (if any) differences between the PM5 and the PM9?

Jaker

Is your car currently DPFI or MPFI? If it's DPFI (2 injectors) it won't run well at all with the PM9, because that one is made to run 4 injectors, and needs the cank angle sensor from the MPFI setup that is inside the distributor.

SweetOh

Good old fashion DPFI.
Its seamed to run fine and no ecu codes :?

I have it plug in and went for a test drive. It has a little smoother accell but less then the PM5. The PM5 has more bite in higher rpm that is noticeable in 1st and 2nd gear. As of the PM9 when I floor it, it's smooth but not much of a push in high rpm.
I’m thinking pm9 is for the d15b1 and or the HF cause my hp is noticeable less, Though will gas mileage go up?

Still any info about would be appreciated.

B18C5-EH2

Sorry for the one month late info, but a PM9 is the Civic STD hatchback ECU - I know because I've still got mine from my 1990 STD hatch I built a D16A6 for.

It is a different ECU than other DX type ECUs as it's for the 70hp DPFI engine found in the 88-91 Civic STD (4-speed) that had a restrictor plate and different cam from all other 1.5L DPFI 88-91 Civic/CR-X/Wagon/Wagovan?sedan 88/91hp engines.

In a nutshell I think the PM9 will make your car run worse as it's got to have different fuel mapping to match the highly restricted 70hp engine it matches.

SweetOh

Kool thanks, yeah i notice a preformance difference between the two.
but i think the pm9 has a little better fuel milage.